It is known to introduce endovascular stent grafts into the vasculature of a patient to bridge an aneurism or damaged portion of the wall of the vasculature. Problems can occur however, where the damage to the vasculature includes or is adjacent to a branch vessel from a main artery because occlusion of the branch vessel may cause permanent damage to the patient.
Examples of such branch vessels are the renal and the mesenteric arteries extending from the aorta.
Fenestrations in a stent graft have been proposed to allow access to the branch vessel from a main stent graft but it is often necessary to provide a side branch graft to maintain access into the branch vessel.
A problem exists, however, with the catheterisation of such a branch vessel to enable deployment of a covered stent or uncovered stent into the side vessel and it is the object of this invention to provide a method to facilitate catheterisation. The problem can be exacerbated in the region of the renal arteries where there are normally two renal arteries substantially adjacent to each other extending from the aorta and is necessary to have two arrangements for catheterisation within the stent graft.
Normally a stent graft introducer device would include a pusher catheter but where catheterisation devices for the branch vessels are to also be included there is not enough room within the containing sheath for a stent graft introducer having regard to the diameter of the vasculature through which it must be introduced to include a full pusher catheter.
The overall diameter of the delivery device is restricted by the diameter of the vessels through which access is to be obtained. The usual route to access the aorta using the Seldinger technique is via the femoral and iliac arteries and this restricts the diameter of a delivery device to about 24 French (7.6 mm diameter).
These arrangements have therefore required a considerable redesign of the delivery device and it is to that redesign that the present invention is directed.
Throughout this specification the term distal with respect to a portion of the aorta, a deployment device or a prosthesis means the end of the aorta, deployment device or prosthesis further away in the direction of blood flow away from the heart and the term proximal means the portion of the aorta, deployment device or end of the prosthesis nearer to the heart. When applied to other vessels similar terms such as caudal and cranial should be understood.